Gas cylinder



FIG. 1 is a perspective view of the gas cylinder in an upright position;

FIG. 2 is a left side elevational view of the gas cylinder, the right side elevation view being a mirror image thereof;

FIG. 3 is a front elevational view of the gas cylinder, the rear elevation view being a mirror image thereof;

FIG. 4 is a top plan view of the gas cylinder; and,

FIG. 5 is a bottom plan view of the gas cylinder.

The structural features depicted in broken lines have been shown for purposes of illustrating portions of the gas cylinder that form no part of the claimed design. 

CLAIM The ornamental design for a gas cylinder, as shown and described. 